changed deleteVoxelCodeFromTree() to use recursion to allow for proper unwinding, updating of parent path
add markWithChangedTime() method as public method

Conflicts:
	libraries/voxels/src/VoxelNode.cpp
	libraries/voxels/src/VoxelNode.h
allow avatar agents to ask for audio loopback
fixed bug in recursive delete that caused animation ghosts
Made readCodeColorBufferToTree() use self contained recursion so we can
implement color averaging properly
Merge branch 'master' of github.com:worklist/hifi into echo
add missing cstring include for memcpy
Merge pull request #491 from PhilipRosedale/master

Sensor fusion for more stable gyros, camera tightness 0 option
conditional cleanup in Agent to re-fire PRB
Merge pull request #493 from birarda/echo

add back audio echo option
added method for general subtree change bookkeeping
Merge pull request #495 from ZappoMan/recursive_voxel_delete

Fixes to delete voxel and color/add voxel to allow for unwinding color reaveraging
Added debug->run timing tests option to speed test some common functions  (please add some more, bottom of util.cpp